1.. Permission is granted to copy, distribute and/or modify this
2.. document under the terms of the GNU Free Documentation License,
3.. Version 1.1 or any later version published by the Free Software
4.. Foundation, with no Invariant Sections, no Front-Cover Texts
5.. and no Back-Cover Texts. A copy of the license is included at
6.. Documentation/userspace-api/media/fdl-appendix.rst.
7..
8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
9
10.. _FE_SET_TONE:
11
12*****************
13ioctl FE_SET_TONE
14*****************
15
16Name
17====
18
19FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
20
21
22Synopsis
23========
24
25.. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode tone )
26    :name: FE_SET_TONE
27
28
29Arguments
30=========
31
32``fd``
33    File descriptor returned by :ref:`open() <frontend_f_open>`.
34
35``tone``
36    an integer enumered value described at :c:type:`fe_sec_tone_mode`
37
38
39Description
40===========
41
42This ioctl is used to set the generation of the continuous 22kHz tone.
43This call requires read/write permissions.
44
45Usually, satellite antenna subsystems require that the digital TV device
46to send a 22kHz tone in order to select between high/low band on some
47dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
48this is done using the DiSEqC ioctls.
49
50.. attention:: If more than one device is connected to the same antenna,
51   setting a tone may interfere on other devices, as they may lose the
52   capability of selecting the band. So, it is recommended that applications
53   would change to SEC_TONE_OFF when the device is not used.
54
55
56Return Value
57============
58
59On success 0 is returned.
60
61On error -1 is returned, and the ``errno`` variable is set
62appropriately.
63
64Generic error codes are described at the
65:ref:`Generic Error Codes <gen-errors>` chapter.
66